Julie and Sam have a bag of 36 colored balls, with each ball having a distinct size. Within the bag there are 12 red balls, 12 blue balls, and 12 yellow balls. How many sets of 4 balls are missing at...

You can solve this by looking at the number of ways in which 4 balls of the same color are chosen
You can solve this by looking at the number of ways in which 4 balls of the same color are chosen.
Since each ball is distinguishable in size, among each color all are DIFFERENT.
Number of ways of selecting any ball of one...